For the fabrication of storage apparatus and switching elements, as, for example, miniature remanent reed relays which function without an external soft-magnetic return connection, materials are required which have a coercive force H.sub.c of 16 to 80 Amperes per centimeter (A/cm), a remanence ratio J.sub.r /J.sub.s of at least 0.80 as well as a remanence flux density B.sub.r = J.sub.r of at least 1.3 Tesla, and which are, in addition, distinguished by their good sealability in suitable glasses. These materials, furthermore, should be conveniently deformable in a hard state, and should exhibit a relatively high elasticity under magnetically favorable conditions. In addition, they should have a relatively low saturation magnetostriction .lambda.s. Note: 1 Ampere per centimeter = 1.256 Oerstedt, and 1 Tesla = 1 Volt-sec. per square metre = 10,000 Gauss.
In order to meet these magnetic, thermo-mechanical, and related technological needs, the use of magnetic semi-hard alloys has been proposed, such as a cobalt-iron-nickel-niobium-alloy, which, additionally, can contain at least one metal from the group tantalum, titanium, vanadium, zirconium, molybdenum, chromium, and tungsten (German "Auslegeschrift" 2,244,925) and a cobalt-nickel-iron-aluminum-titanium alloy (West German Pat. application No. P. 24 31 874). In the first cited alloy, the weight ratio of cobalt to iron is in the range from 3 : 2 to 1 : 2, the weight ratio of nickel to iron is in the range from 1 : 1 to 1 : 3, and the portion of niobium, or of niobium plus an additional metal, is 1 to 5 weight percent. For the use contemplated, this alloy is hardened at 600.degree. to 900.degree. C, and subsequently cold deformed by at least 75% with intermediate annealings at temperatures of at least 600.degree. C.
The composition of the second cited alloy is within the domain of the multi-component system cobalt-(nickel+Aluminum+Titanium)- iron which is (delimited) by the graphically representable polygonal course
A (10 % co; 25 % (Ni+Al+Ti) ; 65 % Fe) - PA1 B (10 % co; 45 % (Ni+Al+Ti) ; 45 % Fe) - PA1 C (45 % co; 30 % (Ni+Al+Ti) ; 25 % Fe) - PA1 D (45 % co; 15 % (Ni+Al+Ti) ; 40 % Fe) - A,
wherein the aluminum content ranges from 1 to 4% and the titanium-content ranges from 0.5 to 4% in such proportion that the sum of the aluminum and titanium contents is 2 to 5%. This alloy is intermediately annealed at 700.degree. to 900.degree. C, and cold worked (deformed) by at least 70% and is subjected to a final annealing at 500.degree. to 700.degree. C for 0.5 to 4 hours.
Disadvantageously with these alloys, especially those whose composition lies under the dotted curve T. . . S in FIG. 1 herein, the face centered cubic (fcc.), high temperature phase transforms itself with the body centered cubic (bcc.), low temperature phase which latter phase is partially diffusion conditioned and partially martensitic. The resulting anomaly which occurs during thermal expansion of these so connected alloys has the effect that glass seals therewith, especially when such seals are produced under automated conditions, either do not have the quality needed (because of the tensions which arise) or have such needed quality only as a result of great manufacturing expense.
The cobalt-nickel-iron-niobium alloy belonging to the prior art furthermore has the additional disadvantage that even in the case of a favorable sealing the primary demand for a great metal-glass bond strength is not achieved.